tetano
Editor, Senior Moderator
Infect Control Hosp Epidemiol
. 2020 Jun 8;1-32.
doi: 10.1017/ice.2020.282. Online ahead of print.
Air and Environmental Sampling for SARS-CoV-2 Around Hospitalized Patients With Coronavirus Disease 2019 (COVID-19)
Vincent Chi-Chung Cheng[SUP] #[/SUP][SUP] 1 2 [/SUP], Shuk-Ching Wong[SUP] #[/SUP][SUP] 2 [/SUP], Veronica Wing-Man Chan[SUP] 2 [/SUP], Simon Yung-Chun So[SUP] 1 [/SUP], Jonathan Hon-Kwan Chen[SUP] 1 [/SUP], Cyril Chik-Yan Yip[SUP] 1 [/SUP], Kwok-**** Chan[SUP] 3 [/SUP], Hin Chu[SUP] 3 [/SUP], Tom Wai-Hin Chung[SUP] 1 [/SUP], Siddharth Sridhar[SUP] 3 [/SUP], Kelvin Kai-Wang To[SUP] 3 [/SUP], Jasper Fuk-Woo Chan[SUP] 3 [/SUP], Ivan Fan-Ngai ****[SUP] 4 [/SUP], Pak-Leung Ho[SUP] 3 [/SUP], Kwok-Yung Yuen[SUP] 3 [/SUP]
Affiliations
Abstract
Background: The role of severe respiratory coronavirus virus 2 (SARS-CoV-2)-laden aerosols in the transmission of coronavirus disease 2019 (COVID-19) remains uncertain. Discordant findings of SARS-CoV-2 RNA in air samples were noted in early reports.
Methods: Sampling of air close to 6 asymptomatic and symptomatic COVID-19 patients with and without surgical masks was performed with sampling devices using sterile gelatin filters. Frequently-touched environmental surfaces near 21 patients were swabbed before daily environmental disinfection. The correlation of viral load of patients' clinical samples and environmental samples were analyzed.
Results: All the air samples were negative for SARS-CoV-2 RNA in the 6 patients singly isolated inside airborne infection isolation rooms (AIIR) with 12 air change per hour. Nineteen (5.0%) of 377 environmental samples near 21 patients were RT-PCR positive with a median viral load of 9.2x102 copies/ml (range: 1.1x102 to 9.4x104 copies/ml). The contamination rate was highest on patients' mobile phone (7.8%, 6/77), followed by bed rail (5.4%, 4/74) and toilet door handle (5.3%, 4/76). There was a significant correlation between viral load ranges in clinical samples and positivity rate of environmental samples (p < 0.001).
Conclusion: SARS-CoV-2 RNA was not detectable by air sampler which suggests that airborne route is not the predominant mode of transmission of COVID-19. Wearing of surgical mask, appropriate hand hygiene and thorough environmental disinfection are sufficient infection control measures for COVID-19 patients isolated singly in AIIR. But this may not apply during aerosol generating procedures or in cohort wards with large number of COVID-19 patients nursed together.
. 2020 Jun 8;1-32.
doi: 10.1017/ice.2020.282. Online ahead of print.
Air and Environmental Sampling for SARS-CoV-2 Around Hospitalized Patients With Coronavirus Disease 2019 (COVID-19)
Vincent Chi-Chung Cheng[SUP] #[/SUP][SUP] 1 2 [/SUP], Shuk-Ching Wong[SUP] #[/SUP][SUP] 2 [/SUP], Veronica Wing-Man Chan[SUP] 2 [/SUP], Simon Yung-Chun So[SUP] 1 [/SUP], Jonathan Hon-Kwan Chen[SUP] 1 [/SUP], Cyril Chik-Yan Yip[SUP] 1 [/SUP], Kwok-**** Chan[SUP] 3 [/SUP], Hin Chu[SUP] 3 [/SUP], Tom Wai-Hin Chung[SUP] 1 [/SUP], Siddharth Sridhar[SUP] 3 [/SUP], Kelvin Kai-Wang To[SUP] 3 [/SUP], Jasper Fuk-Woo Chan[SUP] 3 [/SUP], Ivan Fan-Ngai ****[SUP] 4 [/SUP], Pak-Leung Ho[SUP] 3 [/SUP], Kwok-Yung Yuen[SUP] 3 [/SUP]
Affiliations
- PMID: 32507114
- DOI: 10.1017/ice.2020.282
Abstract
Background: The role of severe respiratory coronavirus virus 2 (SARS-CoV-2)-laden aerosols in the transmission of coronavirus disease 2019 (COVID-19) remains uncertain. Discordant findings of SARS-CoV-2 RNA in air samples were noted in early reports.
Methods: Sampling of air close to 6 asymptomatic and symptomatic COVID-19 patients with and without surgical masks was performed with sampling devices using sterile gelatin filters. Frequently-touched environmental surfaces near 21 patients were swabbed before daily environmental disinfection. The correlation of viral load of patients' clinical samples and environmental samples were analyzed.
Results: All the air samples were negative for SARS-CoV-2 RNA in the 6 patients singly isolated inside airborne infection isolation rooms (AIIR) with 12 air change per hour. Nineteen (5.0%) of 377 environmental samples near 21 patients were RT-PCR positive with a median viral load of 9.2x102 copies/ml (range: 1.1x102 to 9.4x104 copies/ml). The contamination rate was highest on patients' mobile phone (7.8%, 6/77), followed by bed rail (5.4%, 4/74) and toilet door handle (5.3%, 4/76). There was a significant correlation between viral load ranges in clinical samples and positivity rate of environmental samples (p < 0.001).
Conclusion: SARS-CoV-2 RNA was not detectable by air sampler which suggests that airborne route is not the predominant mode of transmission of COVID-19. Wearing of surgical mask, appropriate hand hygiene and thorough environmental disinfection are sufficient infection control measures for COVID-19 patients isolated singly in AIIR. But this may not apply during aerosol generating procedures or in cohort wards with large number of COVID-19 patients nursed together.